On Fri, 2021-07-30 at 09:25 -0400, Benjamin Coddington wrote: > I have some folks unhappy about behavior changes after: 479219218fbe > NFS: > Optimise away the close-to-open GETATTR when we have NFSv4 OPEN > > Before this change, a client holding a RO open would invalidate the > pagecache when doing a second RW open. > > Now the client doesn't invalidate the pagecache, though technically > it could > because we see a changeattr update on the RW OPEN response. > > I feel this is a grey area in CTO if we're already holding an open. > Do we > know how the client ought to behave in this case? Should the > client's open > upgrade to RW invalidate the pagecache? > It's not a "grey area in close-to-open" at all. It is very cut and dried. If you need to invalidate your page cache while the file is open, then by definition you are in a situation where there is a write by another client going on while you are reading. You're clearly not doing close- to-open. The people who are doing this should be using uncached I/O. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
